Towing tractor



FIG. 1 is a front elevational view of a towing tractor, showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a cross-sectional view thereof, taken along line A--A of FIG. 6. 

The ornamental design for a towing tractor, as shown and described. 